Hello, and thanks in advance for reading. I am hoping to find someone with expertise in Open Firmware and preferably with experience installing OpenBSD on an iMac,1 (CRT model).

I installed Debian Linux on this iMac long ago. After burning the macppc flavor of install64.iso to a disc, I turned on the iMac, inserted the disc, and arrived at yaboot. From there I pressed '1' to boot from disc, and arrived at the OpenBSD installer.

The installation seemed to run without a hitch. Because I have no intention of using the iMac for anything but OpenBSD, I chose the Whole Disk option when setting up the partitions.

After the installation finished and I was prompted to reboot, I did so and arrived at Open Firmware as expected. I turned to reference the next step in the process, and in these 10-15 seconds the iMac seemed to proceed with the boot process on its own. The next thing I saw was the installation CD again. Figuring I hadn't been quick enough to interrupt the iMac booting back to the CD, I rebooted again.

At this point I noticed a new sort of hum coming from the computer. It sounds a bit like the familiar sound of the hard drive spinning, but with a slightly lower pitch. It's a fairly faint sound. This sound holds for a few seconds, and then changes to an unfamiliar sound for a second that sounds a bit like a square wave, with a low and slightly descending pitch. It is similarly quiet. Additionally, while this tone is sounding, a sort of interference in the scanlines can be faintly seen crawling up and down the screen. As if the cathode ray is vibrating at a high frequency, maybe? The two sounds continue to alternate for about 90 seconds before abruptly falling silent.

This time, Open Firmware did not come up automatically. Instead the computer seemed to do nothing for several minutes before flashing the Mac "no disk found" symbol.

I rebooted the computer once more, this time holding 'Option'+'O'+'F to arrive back at Open Firmware. I continued with the instructions and attempted to run the command:

Code:

boot ide1:,ofwboot /bsd

The immediate response:

Code:

can't OPEN: ide1:,ofwboot
ok

Hoping that my drive/partition was simply under a different alias than ide1, and hoping that I wasn't hearing the sounds of a failed hard drive, I attempted running the command with different device aliases. "devalias" delivers the following output:

Replacing ide1 with ide0 in the boot command yielded the same immediate result. However, when using the alias "hd", there is a 64 second pause before the same failure message is returned.

Attempting to diagnose whether the installer had successfully written anything to a disk, and on which device it was, I switched to the dir command:

Code:

dir ide0

Same basic result:

Code:

can't OPEN the DIR device
ok

The hd alias responds the same, after a 64 second delay.

Having been unable to find any proof of any data anywhere, I decided to run the installer again to make sure I hadn't missed something. So I ran the following command:

Code:

boot cd:,ofwboot /6.4/macppc/bsd.rd

The response:

Code:

can't OPEN: cd:,ofwboot
ok

So, I attempted to probe the cd:

Code:

dir cd

Result:

Code:

can't OPEN the DIR device
ok

I figure it's possible here that the alias is set improperly and I am not actually probing the disc drive, but I had already explored the other aliases in my search for the hard drive. So, I decided to turn off the computer and try for the standard Mac method of booting from CD: holding the 'C' key at boot.

After holding the key for 2 minutes and 20 seconds, the disc drive spins down.
After holding the key for 4 minutes and 25 seconds, the screen flashes white.
After holding the key for 5 minutes and 30 seconds, the iMac finally gives up and begins to flash the "missing Mac OS folder" icon.

Next I tried the alternate method of getting a Mac to boot from CD: holding the 'Option' key at boot.

The boot selector screen comes up fine but shows no options. A cursor in the corner shows that the computer is presumably scanning for bootable drives, but none is ever found and eventually the cursor changes to a standard pointer.

My Google searches failed to yield anybody with the same isssue. However I followed steps intended for general issues with booting and Open Firmware: I reset the PRAM by holding 'Option'+'P'+'R at boot and waiting for three startup chimes. I also reset NVRAM via these commands in Open Firmware:

Code:

reset-nvram
set-defaults
reset-all

Following these steps, no change was observed in the behavior described above. I then learned of the PMU button on the iMac's logic board which resets the PMU. After disconnecting the computer, moving it, opening its access port, and pressing the PMU button, I once more attempted every method of booting and probing both the CD drive and the hard drive. No changes were observed.

I had a passing thought that this model of iMac has a FireWire port and therefore can be booted in target disk mode. I also have a FireWire card in my Windows PC which is used for other peripherals. Having never attempted it before, I found the software MacDrive which purports to be able to mount the drives of Macs booted in target mode.

After installing the MacDrive software, rebooting, connecting the FireWire cable, and starting the iMac while holding the 'T' key, the iMac did not seem to actually reach the target disk mode. The machine turns on and the disks spin, but the screen remains black. Not long after, I find that Windows has blue screened!

The Windows PC then rebooted and ran a disk check before arriving at the Windows 7 logo. Then, it blue screened again.

I unplugged the FireWire cable, and Windows 7 was able to successfully boot. I decided to attempt the connection one more time, and again Windows 7 blue screened and would continue to do so mid-boot until the iMac was disconnected.

Curious, I connected a 2011 MacBook Pro to the PC via FireWire, and started it in target disk mode. I was not able to get MacDrive to see any disk, but Windows does not blue screen!

So, that's where I'm at. I could easily understand an 18 year old hard drive giving up the ghost during/following the installation process, but the fact that I can also no longer access the disc drive that was just working (and worked once and only once immediately following the installation) has me scratching my head.

Has the PCI bus or something like that abruptly failed, taking out both the hard drive and the disc drive?

Or has the OpenBSD installation somehow messed with Open Firmware in some way that cannot be fixed via resetting PRAM, NVRAM, and the PMU?